It's causing more damage than benefit

IYHO, of course. Personally speaking I see it as neither a huge boon nor a terrible disaster.

and fixing old code is easy

It really isn't. Technical debt is a huge problem within the industry - just ask any COBOL programmer (if they will let you onto their superyacht). I have seen comments like

# This next line is essential for this subroutine to work but I don't 
+know why.
# DO NOT TOUCH OR REMOVE IT!
[download]

too many times to be shocked or surprised. Any time you touch old code you risk breakage and the older the code the higher the risk.

The more logical Perl is constructed, the easier it is to promote.

Completely agree (so long as it doesn't end up just being a dialect of python ;-p)